Welding near solvents

Welding near solvents. It is important to ensure that parts to be welded are free of cleaning solvents. Ultraviolet rays and heat from welding can decompose certain solvents to produce hazardous gases. Accordingly, the atmosphere in... 

Open Flames or Hot Surfaces No degreaser should be installed near open flames or near high-temperature surfaces (above 750°F [399°C]). Welding and heat treatment operations and space heaters should not be located in proximity to solvent degreasing equipment. When these operations are in the same general area as solvent degreasing equipment, precautions should be taken, such as enclosures and local ventilation to ensure that no traces of solvent vapors enter these areas. 

If such operations must be located near a degreaser, solvent vapors must be vented out of the building. Outside air should be provided for combustion devices. Ultraviolet radiation, such as from a welding arc, can cause similar decomposition. Smoking should be prohibited in the vicinity of degreasing operations. 

At 20 C saturated vapor/air mixture contains 560mg HCH/m Remarkably volatile, despite being a solid. The subatanci la usually used in dissolved form In aflammabls solvent an thus can present fire and explosion hazards. Under no circumstsmces use near flame or hot surface orwhen welding. 

The combination of properties that makes fiuorocarbons highly desirable engineering plastics also makes them nearly impossible to heat or solvent weld and very difficult to bond with adhesives withont proper snrface treatment. Fluorocarbons such as polytetraflu-oroethylene (TFE), polyfluoroethylene propylene (FEP), polychlorotrifluoroethylene (CTEE), and polymonochlorotriflnoroethylene (Kel-F) are notoriously difficult to bond because of their low surface tension and chemical resistance. However, epoxy and poly-nrethane adhesives offer moderate strength if the fluorocarbon is treated prior to bonding. 

The combination of properties that makes fluorocarbons highly desirable engineering plastics also makes them nearly impossible to heat or solvent weld and very difficult to bond with adhesives without proper surface treatment. The most common surface preparation for... 

Plastic adhesives are used in the household or for model-making. They are able to bond nearly all plastics, for example, polystyrene, ABS, plexiglass, polycarbonate, and rigid PVC. Plastic adhesives partly belong to the solvent-welding adhesives. As they contain solvents such as butyl acetate, the surface to be bonded is slightly solvated, and... 

Phosgene, produced when metals have been cleaned with chlorinated hydrocarbons or the welding is taking place near chlorinated solvents... 

---